Fuel supply system

ABSTRACT

A fuel supply system supplies fuel in a fuel tank to a fuel consumption apparatus. The system includes a subtank, a pump unit, and an urging device. The subtank is received in the fuel tank and has a communicating hole at a bottom of the subtank. Part of fuel, which is stored in the fuel tank, is stored in the subtank. The outside and inside of the subtank communicate through the hole. The pump unit is received in the subtank and has a supply pump part, which supplies fuel in the subtank to the apparatus, and a pumping part, which pumps up fuel outside the subtank into the subtank. The pumping part has a suction part, which suctions fuel outside the subtank through the hole. The urging device urges the pump unit directly or indirectly toward the bottom of the subtank.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on and incorporates herein by reference Japanese Patent Application No. 2007-191145 filed on Jul. 23, 2007, and Japanese Patent Application No. 2008-92487 filed on Mar. 31, 2008.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fuel supply system.

2. Description of Related Art

A fuel supply system, which supplies fuel stably to a fuel consumption apparatus even when fuel in a fuel tank decreases, is known (see, e.g., JP-T-2003-532009 corresponding to U.S. Pat. No. 6,425,734B2). The fuel supply system includes a supply pump part, which supplies fuel in a subtank to the fuel consumption apparatus, and a pump part, which pumps up fuel that is outside the subtank into the subtank. The pump part includes a suction opening portion, which is inserted into a communicating hole formed on a bottom portion of the subtank.

However, if the fuel pump is not fixed to the subtank, a vibration generated when a vehicle travels is transmitted to the subtank, and the subtank and the fuel pump move independently of each other. Accordingly, the suction opening and the communicating hole become worn therebetween, and thereby a gap, through which the inside and outside of the subtank communicate, is formed. As a result, fuel in the subtank leaks through the gap, and efficiency of the fuel pump is lowered.

Conventionally, a fuel supply system having a subtank and a fuel pump is known. The subtank is received in a fuel tank and opens at its upper portion. Furthermore, the subtank is formed in a cylindrical shape having a bottom, and fuel in the fuel tank is temporarily stored in the subtank. The fuel pump is received in the subtank to supply fuel in the subtank to the outside of the fuel tank. Moreover, the fuel pump pumps up fuel into the subtank (see JP-T-2003-532009).

The fuel pump includes two pump parts, that is, a supply pump part, which suctions the fuel in the subtank and discharges the fuel into the outside of the fuel tank, and a pumping part, which suctions fuel outside the subtank and discharges the fuel into the subtank. An inlet, through which the fuel outside the subtank is suctioned and the fuel is supplied to the pumping part, and a discharge opening, through which the suctioned fuel is discharged into the subtank, are formed at an end portion of the fuel pump. The inlet is inserted in an opening, which is formed at a bottom of the subtank, to be exposed to the outside of the subtank.

However, the inlet is formed at the end portion of the fuel pump, which is opposed to the bottom of the subtank. Accordingly, when the fuel pump is assembled in the subtank, the opening of the subtank and the inlet of the fuel pump are located in blind spots in relation to an operator of the assembly operation. In other words, the operator cannot perform the assembly operation visually identifying the opening and the inlet. Thus, it becomes difficult for the operator to insert the inlet in the opening, and thereby operating efficiency deteriorates. As a result, the reduction of manufacturing cost of the fuel supply system is hindered.

SUMMARY OF THE INVENTION

The present invention addresses the above disadvantages. Thus, it is an objective of the present invention to provide a fuel supply system, which limits fuel leakage from a subtank to alleviate deterioration of pump efficiency of a fuel pump.

It is another objective of the present invention to provide a fuel supply system, which improves operating efficiency when the fuel supply system is assembled to reduce its manufacturing cost.

To achieve these objectives of the present invention, there is provided a fuel supply system that is configured to supply fuel in a fuel tank to a fuel consumption apparatus. The system includes a subtank, a pump unit, and an urging means. The subtank is received in the fuel tank and has a communicating hole at a bottom of the subtank. A part of fuel, which is stored in the fuel tank, is stored in the subtank. An outside and an inside of the subtank communicate through the communicating hole. The pump unit is received in the subtank and has a supply pump part, which supplies fuel in the subtank to the fuel consumption apparatus, and a pumping part, which pumps up fuel outside the subtank into the subtank. The pumping part has a suction part, which suctions fuel outside the subtank through the communicating hole. The urging means is for urging the pump unit one of directly and indirectly toward the bottom of the subtank.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with additional objectives, features and advantages thereof will be best understood from the following description, the appended claims and the accompanying drawings in which.

FIG. 1 is a sectional view illustrating a fuel supply system according to a first embodiment of the invention;

FIG. 2 is a diagram illustrating the fuel supply system viewed from a direction in FIG. 1;

FIG. 3A is an exploded view illustrating the fuel supply system according to the first embodiment;

FIG. 3B is an exploded view illustrating the fuel supply system according to the first embodiment;

FIG. 3C is an exploded view illustrating the fuel supply system according to the first embodiment;

FIG. 4 is a sectional view illustrating a fuel supply system according to a second embodiment of the invention;

FIG. 5 is a plan view illustrating a bracket shown in FIG. 4;

FIG. 6 is a sectional view illustrating a main portion of a pressing pawl part of the bracket;

FIG. 7 is a sectional view illustrating a main portion of an engagement part of the bracket;

FIG. 8 is another sectional view illustrating the main portion of the pressing pawl part of the bracket;

FIG. 9 is a sectional view illustrating that a filter assembly is fitted into a communicating hole of a subtank according to the second embodiment;

FIG. 10 is an exploded view illustrating the fuel supply system according to the second embodiment;

FIG. 11 is a sectional view illustrating a fuel supply system according to a third embodiment of the invention;

FIG. 12 is a top view of a subtank of the fuel supply system shown in FIG. 11;

FIG. 13 is a top view of a pump unit of the fuel supply system shown in FIG. 11;

FIG. 14A is a diagram illustrating a process in which the fuel supply system shown in FIG. 11 is assembled;

FIG. 14B is a diagram illustrating another process in which the fuel supply system shown in FIG. 11 is assembled;

FIG. 15 is a top view illustrating a pump unit of a fuel supply system according to a fourth embodiment of the invention;

FIG. 16 is a top view illustrating a pump unit of a fuel supply system according to a modification of the fourth embodiment;

FIG. 17 is a perspective view illustrating a bracket attached to a filter case of a fuel supply system according to a fifth embodiment of the invention;

FIG. 18 is a sectional view illustrating the bracket in FIG. 17 and the filter case when the bracket is attached to the filter case;

FIG. 19 is a top view illustrating a subtank of the fuel supply system according to the fifth embodiment;

FIG. 20A is a side view illustrating a subtank of a fuel supply system according to a sixth embodiment of the invention;

FIG. 20B is a top view illustrating the subtank of the fuel supply system according to the sixth embodiment;

FIG. 21 is a sectional view illustrating a bracket of the fuel supply system according to the sixth embodiment;

FIG. 22 is a diagram illustrating the bracket viewed from a direction XXII in FIG. 21;

FIG. 23 is a sectional view illustrating a bracket of a fuel supply system according to a modification of the sixth embodiment; and

FIG. 24 is a diagram illustrating the bracket viewed from a direction XXIV in FIG. 23.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the invention are explained below with reference to drawings. The same numerals are used in the drawings to indicate the same or equivalent parts in the following embodiments.

First Embodiment

FIG. 1 shows a fuel supply system 1, which is disposed in a fuel tank 2 installed in a vehicle. Upward and downward directions shown by a arrow in FIG. 1 indicate directions with respect to a direction of gravitational force of the fuel tank 2 that is installed in the vehicle. The fuel supply system 1 supplies fuel in the fuel tank 2 to a fuel consumption apparatus (e.g., internal combustion engine).

As shown in FIG. 1, the fuel supply system 1 is inserted in the fuel tank 2 from an opening 21 formed on a ceiling portion of the fuel tank 2, and is disposed on a bottom 22 of the fuel tank 2. A flange 3 as a “lid member” is attached to the opening 21 so as to block the opening 21.

The fuel supply system 1 includes the subtank 4 and a pump unit 5, which is attached to the subtank 4 received in the fuel tank 2.

The flange 3 is made of resin and formed generally in a shape of a disk. A shaft 31, which connects the flange 3 and the hydraulic pump unit 5, is fixed to the flange 3 by press fitting or the like so as to extend toward the bottom 22 of the fuel tank 2. In the first embodiment, two shafts 31 are provided for the flange 3. The connecting structure between the flange 3 and the hydraulic pump unit 5 is described in greater detail hereinafter.

A fuel discharge pipe 33 and an electric connector 34 are formed from resin integrally with the flange 3. The fuel discharge pipe 33 is connected to the pump unit 5 through the hose 35, and supplies fuel discharged from the hydraulic pump unit 5 to the internal combustion engine outside the fuel tank 2.

The electric connector 34 is electrically connected to an electric connector (not shown) provided in the pump unit 5 through a lead wire and a feeding connector (not shown), to supply electric power to the pump unit 5.

The subtank 4 is made of resin, and includes a generally disk-shaped bottom 41 and a side wall 44, which extends upward from an outer circumference edge portion of the bottom 41. Part of fuel in the fuel tank 2 is stored in the subtank 4. A communicating hole 42, through which the inside and outside of the subtank 4 communicate, is formed on the bottom 41. A leg 43, which extends toward the bottom 22 of the fuel tank 2, is formed around the communicating hole 42. A part of a filter assembly 56 corresponding to a “suction part” is fitted into the communicating hole 42.

As shown in FIG. 2, a first guide plate 46, which guides a guiding projection portion 87 (indicated by a short dashes line) toward the bottom 41, the guiding projection portion 87 projecting from a filter case 8 (indicated by a short dashes line and described in greater detail hereinafter) to its outer circumferential side, is formed on an inner wall side of the side wall 44 of the subtank 4 from an upper end portion of the subtank to the bottom 41. Second guide plates 47, which guide the filter assembly 56 to the communicating hole 42, are formed around the communicating hole 42 to extend upward from the bottom 41. The filter assembly 56 is easily fitted into the communicating hole 42 using the first and second guide plates 46, 47 when attaching the pump unit 5 to the subtank 4.

As shown in FIG. 11 the pump unit 5 includes a fuel pump 51, a fuel filter 88, a pressure regulator 89, and the filter assembly 56. The fuel pump 51 includes a supply pump part 511, which suctions fuel in the subtank 4 and supplies the fuel to the internal combustion engine, and a pumping part 521, which pumps up fuel outside the subtank 4 into the subtank 4.

The fuel pump 51 includes an impeller 53, which has an outer circumference side vane part 531 and an inner circumference side vane part 532, a passage member 54 having an arc-shaped outer circumference side pump passage 541, which follows a shape of the outer circumference side vane part 531, and an arc-shaped inner circumference side pump passage 542, which follows a shape of the inner circumference side vane part 532, and an electric motor part 55, which drives the impeller 53 to rotate. The supply pump part 511 includes the outer circumference side vane part 531 and the outer circumference side pump passage 541, and the pumping part 521 includes the inner circumference side vane part 532 and the inner circumference side pump passage 542. When the impeller 53 is driven by the electric motor part 55 to rotate, the vane parts 531, 532 move in the pump passages 541, 542, respectively, and pressures of fuel suctioned into the pump passages 541, 542 are increased.

In the fuel pump 51 of the first embodiment, the two pump parts 511, 521 are operated by rotating a single impeller 53. Accordingly, the fuel pump is downsized compared to a fuel pump, which has an impeller for each pump part.

A supply pump suction opening 512, which communicates with the outer circumference side pump passage 541, and a pumping suction opening 522, which communicates with the inner circumference side pump passage 542, are formed side by side in a lower end portion of the fuel pump 51. A pumping discharge opening 523, which discharges fuel pumped up by the pumping part 521 into the subtank 4, is formed in the lower end portion of the fuel pump 51 in addition to the two suction openings 512, 522. Furthermore, a supply pump discharge opening 513, which discharges fuel pumped up by the supply pump part 511, is formed in an upper end portion of the fuel pump 51.

The filter assembly 56, which filters fuel suctioned into the suction openings 512, 522, is attached to the lower end portion of the fuel pump 51. The filter assembly 56 includes an upper case 6, a lower case 7, a supply fuel filter 65, which filters fuel conducted to the supply pump part 511, and a pumping fuel filter 79, which filters fuel conducted to the pumping part 521.

The filter assembly 56 is explained below in detail. The lower case 7 includes a cylindrical portion 71 whose end portions in the vertical direction open, and the pumping fuel filter 79 is attached to a lower opening 72 of the cylindrical portion 71 by welding or the like. A first partition wall 73, which divides the cylindrical portion 71 between upper and lower portions, is formed near a generally central portion of the cylindrical portion 71. A projection 731, which divides the first partition wall 73 into right and left portions, is formed on an upper surface of the first partition wall 73.

A passage 732, which penetrates through the first partition wall 73, is formed in a right side-surface (FIG. 1) of a surface of the first partition wall 73, which is divided into right and left portions by the projection 731. The first partition wall 73 has a check valve 74, which allows only a flow of fuel passing from a lower side to an upper side of FIG. 1 out of those flows of fuel passing through the passage 732. A flanged portion 75 extending to the outer circumference side is formed on an outer wall surface of the cylindrical portion 71 near its generally central part.

A fitted part 76, which is fitted into the communicating hole 42 formed in the bottom 41 of the subtank 4, is formed in a portion of the cylindrical portion 71 below the flanged portion 75. A groove portion is formed in the fitted part 76. An O ring for ensuring sealing properties between the fitted part 76 and the communicating hole 42 is attached on the groove portion.

A shaft supporting part 751 extending from the outer wall surface of the cylindrical portion 71 to the outer circumference side is formed on a portion of the cylindrical portion 71 above the flanged portion 75. The shaft supporting part 751 supports a lower end portion of the shaft 31 of the flange 3, and is positioned on an extension line (alternate long and short dash line) of the shaft 31, as shown in FIG. 1. In the first embodiment, the same number of the shaft supporting parts 751 as the number of the shafts 31 are formed. In addition, the flanged portion 75 and the shaft supporting part 751 may be formed integrally.

The pumping fuel filter 79 is made of nonwoven fabrics obtained by making resin (e.g., polyester, nylon, polypropylene, or polyacethylene) fibrose. Because they have relatively high durability against fuel, by using such materials as the pumping fuel filter 79, a life of the filter assembly 56 is made longer.

The upper case 6 is formed to block an upper opening of the cylindrical portion 71. A second partition wall 66 projecting toward the projection 731 of the first partition wall 73 is formed on an upper end portion 61 of the upper case 6. When the upper case 6 is attached to the lower case 7, two spaces are formed between the upper end portion 61 and the first partition walls 73.

An upper opening 62, which communicates with the left space shown in FIG. 1, is formed in the upper end portion 61. The supply fuel filter 65 is provided in the opening 62. The supply fuel filter 65 is a nonwoven fabric made from a similar material to that of the pumping fuel filter 79. The supply fuel filter 65 is attached to the upper opening 62 by welding, insert molding, or the like.

A first connection 63, which communicates with the left space shown in FIG. 1, is formed on the upper end portion 61. The first connection 63 is connected to the supply pump suction opening 512 of the fuel pump 51. Furthermore, a second connection 64, which communicates with the right space shown in FIG. 1, is formed on the upper end portion 61. The second connection 64 is connected to the pumping suction opening 522 of the fuel pump 51.

When the upper case 6 and the lower case 7, which are configured in the above-mentioned manner, are put together, two passages, that is, a supply fuel passage 561 whose inlet is the upper opening 62 and whose outlet is the first connection 63, and a pumping fuel passage 562 whose inlet is the lower opening 72 and whose outlet is the second connection 64, are formed in the filter assembly 56. By forming the first and second partition walls 73, 66, which divide the space, and the projection 731 inside the filter assembly 56, the structure of a filter becomes simple since the two passages 561, 562 are formed in one member, and the filters 65, 79 are formed for the respective passages 561, 562.

The fuel filter 88 is formed on the outer circumference side of the fuel pump 51 to surround the outer circumference of the fuel pump 51. The fuel filter 88 filters fuel discharged from the supply pump discharge opening 513 of the fuel pump 51.

The fuel filter 88 is received in the filter case 8. The filter case 8 is made of resin, and includes a generally annular space in which the fuel filter 88 is received. The filter case 8 supports the fuel pump 51 in a space, which is further on an inner circumference side of the generally annular space.

An upper end portion 84 of the filter case 8 includes a connection 81 for connecting the supply pump discharge opening 513. A gap between the supply pump discharge opening 513 and the connection 81 is sealed with an O ring or the like. A fuel passage 82, which connects the connection 81 and the fuel filter 88, is formed in the filter case 8. Fuel discharged from the supply pump discharge opening 513 is supplied to the fuel filter 88 through the fuel passage 82.

The pressure regulator 89 is provided at a lower end portion (below the generally annular space) of the filter case 8. The pressure regulator 89 regulates a pressure of fuel, which has passed through the fuel filter 88. The fuel whose pressure has been regulated in the pressure regulator 89 is discharged from a discharge opening 83 formed in the filter case 8. The fuel, which has been discharged from the discharge opening 83, is supplied to the internal combustion engine outside the fuel tank 2 through a hose 35 and the fuel discharge pipe 33. When a pressure of fuel discharged from the fuel pump 51 is equal to or larger than a predetermined value, the fuel having overpressure flows out of a drain port (not shown) of the pressure regulator 89 to return into the subtank 4.

The filter case 8 has a snap fitting part (not shown), which engages a pawl part (not shown) formed in the filter assembly 56 so as to hold the filter assembly 56.

A projection portion 85, which projects from an outer circumference side wall surface of the filter case 8 to the outer circumference side, and the guiding projection portion 87 are formed on the above wall surface. The projection portion 85 has an insertion portion 86 as a guiding portion for supporting a side surface of the shaft 31 by inserting a lower end portion side of the shaft 31 into the inserting portion 86. A diameter of the insertion portion 86 is determined, such that the shaft 31 is movable in the insertion portion 86. As shown in FIG. 2, the guiding projection portion 87 is formed in a position where the guiding projection portion 87 does not overlap with the projection portion 85 and the pressure regulator 89 when the filter case 8 is viewed from above.

Because the lower end portion side of the shaft 31 is inserted in the insertion portion 86, the filter case 8, which supports the fuel pump 51, is guided along an axial direction of the shaft 31. Accordingly, the filter case 8, the fuel pump 51, and the filter assembly 56 are displaced along the axial direction of the shaft 31. In other words, the displacement of the filter case 8 and the like in a radial direction is restricted.

As shown in FIG. 1, a coil spring 32 whose one end portion is supported by the flange 3 and whose other end portion is supported by an upper end surface of the projection portion 85 is provided between the flange 3 and the upper end surface of the projection portion 85. The coil spring 32 is provided such that the shaft 31 passes through its center. The coil spring 32 is an “urging member” for urging the filter case 8 toward the bottom 22 of the fuel tank 2.

In the first embodiment, the filter case 8 is urged toward the bottom 41 of the subtank 4 by the coil spring 32. Accordingly, the fuel pump 51 and the filter assembly 56 are urged indirectly toward the bottom 41 of the subtank 4 by the coil spring 32.

According to the above configuration, the relative displacement between the subtank 4 and the fuel pump 51 is restricted. Consequently, the fuel pump 51 is made to follow the movement of the subtank 4 when the vehicle vibrates and thereby the subtank 4 vibrates.

Therefore, the generation of the gap, through which the inside and outside of the subtank 4 communicate between the communicating hole 42 of the subtank 4 and the filter assembly 56 that serves as the suction part of the fuel pump 51, is limited, and the leakage of fuel pumped up by the pumping part 521 out of the subtank 4 is limited. As a result, deterioration of pump efficiency of the fuel pump 51 is limited.

Moreover, because the fitted part 76 formed at the lower end portion of the filter assembly 56 is fitted into the communicating hole 42 of the subtank 4, displacement of the fuel pump 51 in the radial direction is restricted. Accordingly, the generation of the gap, through which the inside and outside of the subtank 4 communicate, due to the vibration of the subtank 4 in the radial direction, is limited.

In the first embodiment, the shaft 31 is inserted into the insertion portion 86 of the projection portion 85, and thereby the side surface of the shaft 31 is supported by the insertion portion 86. Because of the above structure as well, the displacement of the fuel pump 51 in the radial direction is limited, and thus the generation of the above gap due to the vibration of the subtank 4 in the radial direction is limited.

In the first embodiment, the coil spring 32 is provided between the flange 3 and the projection portion 85 projecting from the filter case 8 in the radial direction. As a result, the fuel pump 51 is urged toward the bottom 41 of the subtank 4 only by attaching the flange 3 to the opening 21 of the fuel tank 2.

In addition, the subtank 4 is urged against the bottom 22 of the fuel tank 2. Thus, even if a distance between the opening 21 and the bottom 22 of the fuel tank 2 varies as a result of expansion or contraction of the fuel tank 2 made of resin because of the variation of its internal pressure due to temperature change or the variation of a fuel amount, the subtank 4 is made to follow the bottom 22 of the fuel tank 2.

In the first embodiment, the projection portion 85, which supports the other end of the coil spring 32, is formed on the filter case 8, and thereby the fuel pump 51 is urged indirectly in the direction of the bottom 41 of the subtank 4. Alternatively, the projection portion 85 may be formed directly on an outer wall of the fuel pump 51 to urge the fuel pump 51 directly toward the bottom 41 of the subtank 4.

Next, workings of the fuel pump 51 are explained below. By operating the electric motor part 55 to rotate the impeller 53, suction force is generated in the supply pump part 511 and the pumping part 521.

Fuel in the subtank 4 flows into the supply fuel passage 561 through the supply fuel filter 65 in the upper opening 62, and is suctioned into the supply pump suction opening 512 through the first connection 63. Then, pressure of the fuel is increased in the supply pump part 511, and the fuel is discharged from the supply pump discharge opening 513.

The fuel discharged from the supply pump discharge opening 513 is supplied to the fuel filter 88 through the fuel passage 82. The pressure of the fuel, which is filtered through the fuel filter 88, is then regulated in the pressure regulator 89, and the fuel is discharged from the discharge opening 83. The fuel discharged from the discharge opening 83 is supplied to the internal combustion engine through the hose 35 and the fuel discharge pipe 33.

On the other hand, fuel outside the subtank 4 flows into the pumping fuel passage 562 through the pumping fuel filter 79 in the lower opening 72, and is suctioned into the pumping suction opening 522 through the passage 732 and the second connection 64. Then, pressure of the fuel is increased in the pumping part 521, and the fuel is discharged from the pumping discharge opening 523. As a result, the fuel is pumped up into the subtank 4.

The attachment of the fuel supply system 1 of the first embodiment is described below with reference to FIGS. 3A to 3C. FIG. 3A shows a state before attaching the pump unit 5 to the subtank 4. FIG. 3B shows a state in which the pump unit 5 is being attached to the subtank 4. FIG. 3C shows a state after attaching the pump unit 5 to the subtank 4.

As shown in FIG. 3A, the pump unit 5, in which the fuel pump 51, the filter assembly 56, the pressure regulator 89, and the filter case 8 are assembled, is arranged over the subtank 4. The flange 3, in which the shaft 31 and the coil spring 32 are assembled, is further arranged over the pump unit 5.

As shown in FIG. 3B, the flange 3 is displaced toward the subtank 4, and then the lower end portion of the shaft 31 is inserted into the insertion portion 86 of the projection portion 85 of the filter case 8. After that, the flange 3 is displaced downward until the lower end portion of the shaft 31 is in contact with the shaft supporting part 751. With the above state maintained, the flange 3 is further pushed downward, such that the first guide plate 46 of the subtank 4 guides the guiding projection portion 87 of the filter case 8.

When the flange 3 is pushed downward with the guiding projection portion 87 guided by the first guide plate 46, the fitted part 76 of the filter assembly 56 contacts the second guide plate 47, and the fitted part 76 is guided to the communicating hole 42. Then, the fitted part 76 is fitted into the communicating hole 42. After the lower end portion of the shaft 31 has passed through the insertion portion 86, a slip-off stopping member is attached to the lower end portion of the shaft 31.

Accordingly, by only displacing the flange 3 toward the bottom 41 of the subtank 4 (downward) together with the shaft 31, the fitted part 76 of the filter assembly 56 is easily fitted into the communicating hole 42.

As shown in FIG. 3C, after the fitted part 76 has been fitted into the communicating hole 42, the pushing of the flange 3 is relieved.

Second Embodiment

A second embodiment of the invention is explained below with reference to FIGS. 4 to 10.

In a fuel supply system 1 a of the second embodiment, a means for urging a fuel pump 51 toward a bottom 41 of a subtank 4 is different from that of the first embodiment. Only components, which are different from those of the first embodiment, are explained below.

In the second embodiment, the fuel pump 51 is urged indirectly toward the bottom 41 of the subtank 4 by the bracket 9, which serves as an “urging means” provided on an upper end portion 84 of a filter case 8.

The bracket 9 is made of resin, and includes a main body part 91, which supports the upper end portion 84, an engagement part 94, which engages a side wall 44 of the subtank 4, and a pressing pawl part 96, which serves as an urging part that urges the upper end portion 84. In the second embodiment, the fuel pump 51 is supported by the main body part 91 through the filter case 8. Alternatively, the main body part 91 may directly support the fuel pump 51 if the fuel supply system 1 a does not have the filter case 8. Furthermore, the fuel pump 51 is urged by the pressing pawl part 96 through the filter case 8. Alternatively, the pressing pawl part 96 may directly urge an upper end portion of the fuel pump 51, if the fuel supply system 1 a does not have the filter case 8.

A flange 3 and the subtank 4 are joined with a shaft 31 provided in the flange 3. An insertion portion 86 a, in which the shaft 31 is inserted, is provided on an inner wall surface of a side wall 44 of the subtank 4. The shaft 31 is inserted in the insertion portion 86 a to be movable in its axial direction in the insertion portion 86 a. A coil spring 32 a is provided between the flange 3 and the insertion portions 86 a so as to urge the subtank 4 against a bottom 22 of a fuel tank 2.

Although the first guide plate 46 and the second guide plate 47 are not drawn in FIG. 4, the first guide plate 46 and the second guide plate 47, which guide the filter case 8, may be provided for the subtank 4, similar to the first embodiment shown in FIGS. 1, 2. In such a case, a guiding projection portion 87, which is guided by the first guide plate 46, needs to be provided for the filter case 8 (see FIGS. 1, 2).

The main body part 91 includes a side wall supporting part 92, which is formed in a generally cylindrical shape to cover a side wall of the upper end portion 84 and to support the filter case 8, and a pawl support part 93, which is formed to project from an upper end portion of the side wall supporting part 92 to its inner circumference side, for supporting the pressing pawl part 96.

The pressing pawl part 96 is formed by inflecting a plate-shaped member such that the member projects toward the upper end portion 84. One end portion of the pressing pawl part 96 is supported by an inner circumferential end portion of the pawl support part 93. When the pressing pawl part 96 is in contact with the upper end portion 84, the pressing pawl part 96 bends with its inner circumferential end portion being a fulcrum. Meanwhile, restoring force, which urges the upper end portion 84 toward the bottom 41 of the subtank 4, is generated in the pressing pawl part 96. Accordingly, the fuel pump 51 is urged toward the bottom 41 of the subtank 4. Since the pressing pawl part 96 is formed in a shape of a plate, the bracket 9 has a simple structure.

The engagement part 94 projecting to an outer circumference side of the main body part 91 is formed on a peripheral wall of the side wall supporting part 92 of the main body part 91. In the second embodiment, three engagement parts 94 are formed as shown in FIG. 5. The bracket 9 may have at least more than one engagement part 94. Each of the engagement parts 94 has an engagement hole 95, which engages a pawl part 45 formed on the outer wall surface of the side wall 44 of the subtank 4 (see FIG. 4). By inserting the pawl part 45 into the engagement hole 95, the engagement hole 95 engages the pawl part 45, and thereby the upward displacement of the main body part 91 is restricted. In addition, by displacing the engagement part 94 of the second embodiment downward from the upper part of the subtank 4 along the side wall 44, the pawl part 45 is inserted into the engagement hole 95. The fuel pump 51 and the bracket 9 are attached to the subtank 4 by only moving the fuel pump 51 and the bracket 9 from the opening side toward the bottom side of the subtank 4. By only moving the fuel pump 51 and the bracket 9 in one direction, their attachment to the subtank 4 is completed. Therefore, the attachment is easy to automatize.

The upward displacement of the main body part 91 is restricted in the state where the pawl part 45 is inserted in the engagement hole 95. Thus, the fuel pump 51 is urged toward the bottom 41 of the subtank 4 through the filter case 8 by the pressing pawl part 96.

The shape of the engagement part 94 may be different from the second embodiment. More specifically, the engagement part 94 may have a pawl part, and a stepped section or engagement hole, which the above pawl part engages may be formed on the side wall 44 of the subtank 4.

Furthermore, a spring member, such as a coil spring, may be employed as the urging part for urging the fuel pump 51 toward the bottom 41 of the subtank 4, instead of the pressing pawl part 96.

Next, characteristics of the pressing pawl part 96 are explained with reference to FIGS. 6 to 9.

FIG. 6 illustrates a variation between a state of the pressing pawl part 96 before the pressing pawl part 96 is in contact with the upper end portion 84, and a state of the pressing pawl part 96 after the pressing pawl part 96 contacts the upper end portion 84. In FIG. 6, the state before the pressing pawl part 96 contacts the upper end portion 84 is indicated by a short dashes line, and the state in which the pressing pawl part 96 is in contact with the upper end portion 84 is indicated by a continuous line.

Urging force with which the pressing pawl part 96 urges the filter case 8 varies according to a flexure amount of the pressing pawl part 96 (displacement of the pressing pawl part 96 in the vertical direction). The urging force becomes large as the flexure amount becomes larger, and the urging force becomes smaller as the flexure amount becomes smaller. In the second embodiment, minimum urging force, with which the pressing pawl part 96 urges the filter case 8 with the engagement part 94 in engagement with the subtank 4, is set.

FIG. 6 illustrates that the pressing pawl part 96 generates the minimum urging force. The minimum urging force is set such that it overcomes inertia force of the pump unit 5, which is generated when the vehicle vibrates. The flexure amount of the pressing pawl part 96 when the pressing pawl part 96 generates the minimum urging force (f) is assumed to be a minimum flexure amount (Imin).

FIG. 7 illustrates that the engagement part 94 is in engagement with the subtank 4. In FIG. 7, a position of the bracket 9 when the bracket 9 is pressed to a subtank 4-side as far as possible is indicated by a short dashes line, and a position of the bracket 9 when the pressing pawl part 96 urges the upper end portion 84 downward is indicated by a continuous line.

As shown in FIG. 7, the bracket 9 is configured to engage the subtank 4 by inserting the pawl part 45 of the subtank 4 in the engagement hole 95 of the engagement part 94. As a result, an attachment gap (L) is generated in the vertical direction.

In the second embodiment, characteristics of the pressing pawl part 96 are set such that the attachment gap (L) is smaller than the minimum flexure amount (Imin) of the pressing pawl part 96 when the bracket 9 is located on an uppermost side with the bracket 9 in engagement with the subtank 4 at its engagement part 94. Accordingly, the pressing pawl part 96 urges the filter case 8 downward with the force, which is equal to or larger than the minimum urging force (f).

Similar to FIG. 6, FIG. 8 illustrates the variation between the state of the pressing pawl part 96 before the pressing pawl part 96 is in contact with the upper end portion 84, and the state of the pressing pawl part 96 after the pressing pawl part 96 contacts the upper end portion 84. FIG. 8 illustrates that the pressing pawl part 96 is most bent. In the above state, the height of the upper end portion 84 is generally the same as that of the pawl support part 93, and the pressing pawl part 96 cannot be bent any more upward. Meanwhile, the flexure amount of the pressing pawl part 96 is Imax.

In the second embodiment, as shown in FIG. 9, characteristics of the pressing pawl part 96 are set, such that the maximum flexure amount (Imax) of the pressing pawl part 96 is smaller than a fitted amount (D) of the filter assembly 56, that is, a length of an overlap between the fitted part 76 of the filter assembly 56 and the communicating hole 42 in the vertical direction.

Consequently, even if the filter case 8 pushes up the pressing pawl part 96 and the flexure amount reaches the maximum flexure amount (Imax), when the vehicle travels along a bad road and as a result, vibration, which is stronger than expected, is transmitted to the subtank 4, for example, the separation of the filter assembly 56 from the communicating hole 42 is limited.

Next, the assemblage of the fuel supply system 1 a of the second embodiment is described below with reference to FIG. 10.

As shown in FIG. 10, the pump unit 5, in which the fuel pump 51, the filter assembly 56, the pressure regulator 89 and the filter case 8 are assembled, is arranged over the subtank 4, and the bracket 9 is arranged over the pump unit 5. Furthermore, the flange 3, in which the shaft 31 and the coil spring 32 a are assembled, is arranged over the bracket 9. Then, the pump unit 5, the bracket 9, and the flange 3 are attached to the subtank 4 in this order.

In the second embodiment, each of the pump unit 5, the bracket 9 and the flange 3 is attached to the subtank 4 from above the subtank 4. Therefore, the attachment is easy to automatize.

Third Embodiment

FIG. 11 is a sectional view illustrating that a fuel supply system 210 is disposed in a fuel tank 211 installed in a vehicle. Upward and downward directions indicated by an arrow in FIG. 11 show a direction of gravitational force of the fuel tank 211, which is installed in the vehicle. The fuel supply system 210 supplies fuel in the fuel tank 211 to a fuel consumption apparatus (e.g., internal combustion engine).

The fuel supply system 210 is inserted and installed in the fuel tank 211 through an opening 212, which is formed on a ceiling portion of the fuel tank 211, and is disposed on a bottom 213 of the fuel tank 211. A flange 220 as a “lid member” is attached to the opening 212 to block the opening 212.

The fuel supply system 210 includes the flange 220, a subtank 230, and a pump unit 240.

The flange 220 is made of resin and formed generally in a shape of a disk. A shaft 224, which connects the flange 220 and the pump unit 240, is fixed to the flange 220 by press fitting or the like so as to extend toward the bottom 213 of the fuel tank 211. In the third embodiment, two shafts 224 are provided for the flange 220. A joint structure of the shaft 224 and the pump unit 240 is described in greater detail hereinafter.

The flange 220 is made of resin integrally with a fuel discharge pipe 221 and an electric connector 222. The fuel discharge pipe 221 is connected to the pump unit 240 through a hose 262. Fuel, which is discharged from the pump unit 240, is supplied to the internal combustion engine outside the fuel tank 211 through the fuel discharge pipe 221. The electric connector 222 is electrically connected to a power-receiving connector (not shown) provided for the fuel pump 241 of the pump unit 240 via an electric supply line 223 and a feeding connector (not shown), and electric power is supplied to the fuel pump 241 through the electric connector 222.

The subtank 230 is made of resin, and includes a generally disk-shaped bottom 231 and a side wall 234 extending upward from an outer circumferential edge of the bottom 231. A part of fuel in the fuel tank 211 is temporarily stored in the subtank 230. A through hole 232, which penetrates through the bottom 231, is formed on the bottom 231. A leg 233 extending toward the bottom 213 of the fuel tank 211 is formed around the through hole 232. A part of a filter assembly 270 (to be described in greater detail hereinafter) is fitted into the through hole 232.

FIG. 12 is a top view, in which only the subtank 230 in FIG. 11 is viewed from above. As shown in FIG. 12, a guide part 235 that guides a shaft support part 255, which is provided for the pump unit 240 and supports the shaft 224, and a selvage part 288, which is formed in the filter assembly 270, is formed on an inner wall side of the side wall 234 of the subtank 230. The guide parts 235 hold a side part the shaft support part 255, which projects radially outward from a side part of the pump unit 240, therebetween. As shown in FIG. 11, the guide part 235 is formed from an upper end portion of the subtank 230 to the bottom 231 along an axial direction of the subtank 230. As shown in FIG. 12, two guide parts 235 are formed across the through hole 232.

As shown in FIG. 11, the pump unit 240 includes the fuel pump 241, a fuel filter 250, a pressure regulator 260, and the filter assembly 270.

The fuel pump 241 includes a supply pump part 242, which suctions fuel temporarily stored in the subtank 230 and then supplies the fuel to the internal combustion engine outside the fuel tank 211, and a pumping part 243, which pumps up fuel outside the subtank 230 into the subtank 230.

The fuel pump 241 includes an impeller 244, a passage member 245, which receives the impeller 244, and an electric motor part 246, which drives the impeller 244 to rotate.

The impeller 244 includes an outer circumferential vane part 244 a having vanes, which are arranged side by side in a circumferential direction of the impeller 244, and an inner circumferential vane part 244 b having vanes, which are arranged side by side in the circumferential direction. The passage member 245 includes an outer circumferential pump passage 245 a, which covers the vane part 244 a from its both sides in a rotation axis direction of the impeller 244 and is circularly formed along the vane part 244 a, and an inner circumferential pump passage 245 b, which covers the vane part 244 b from its both sides in the rotation axis direction and is circularly formed along the vane part 244 b.

When the impeller 244 is driven to rotate by the electric motor part 246, the vane parts 244 a, 244 b move in the pump passages 245 a, 245 b respectively, and thereby the pressure of the fuel suctioned by the pump passages 245 a, 245 b is increased.

The supply pump part 242 includes the outer circumferential vane part 244 a and the outer circumferential pump passage 245 a, and the pumping part 243 includes the inner circumferential vane part 244 b and the inner circumferential pump passage 245 b.

In the fuel pump 241 of the third embodiment, the two pump parts 242, 243 are operated simultaneously by only driving a single impeller 244 to rotate. As a result, the fuel pump is downsized compared to a type of fuel pump having an impeller for each pump part.

A supply pump suction opening 247 a, which communicates with the outer circumferential pump passage 245 a, a pumping suction opening 247 b, which communicates with the inner circumferential pump passage 245 b, and a pumping discharge opening 248 b, through which the fuel outside the subtank 230 that has been pumped up by the pumping part 243 is discharged into the subtank 230, are formed in a lower end portion of the passage member 245. A supply pump discharge opening 248 a, through which the fuel in the subtank 230 that has been pumped up by the supply pump part 242 is discharged, is formed in an upper end portion of the fuel pump 241.

The filter assembly 270 is attached to the passage member 245. The filter assembly 270 filters fuel suctioned into the supply pump suction opening 247 a and the pumping suction opening 247 b. The filter assembly 270 includes an upper case 271, a lower case 280, a supply fuel filter 290, and a pumping fuel filter 291. The supply fuel filter 290 filters fuel flowing to the supply pump part 242, and the pumping fuel filter 291 filters fuel flowing to the pumping part 243.

The pumping fuel filter 291 is made of nonwoven fabrics obtained by making resin (e.g., polyester, nylon, polypropylene or polyacethylene) fibrose. Because the above materials have relatively high durability against fuel, a life of the filter assembly 270 is made longer by using the materials as a fuel filter.

The lower case 280 has a cylindrical portion 281 whose end portions in the vertical direction respectively open. The pumping fuel filter 291 is attached to a lower opening part 282 of the cylindrical portion 281 by welding or the like. A first partition wall 283, which divides the cylindrical portion 281 between upper and lower portions, is formed in the central part of the cylindrical portion 281. A projection 284, which divides the first partition wall 283 into right and left portions, is formed on an upper surface of the first partition wall 283.

A passage 285, which penetrates through the first partition wall 283, is formed in a portion of the first partition wall 283 on the right side (FIG. 11) of the projection 284. A check valve 286, through which only the fuel flowing from the lower side toward the upper side among those fuels flowing through the passage 285 can pass, is provided for the above portion.

A press fitting part 287, which is press-fitted into the through hole 232 of the bottom 231 of the subtank 230, is formed on the lower opening part 282 of the cylindrical portion 281. A flanged portion 289 is formed on an outer wall of the cylindrical portion 281 above the press fitting part 287.

Two selvage parts 288, which extend radially outward, are formed on the outer wall of the cylindrical portion 281. The selvage part 288 is capable of being fitted into the guide part 235 of the subtank 230.

FIG. 13 shows a top view of the pump unit 240 viewed from a direction XIII FIG. 11. In FIG. 13, the part indicated by a continuous line illustrates a filter case 251, and the part indicated by a short dashes line illustrates the filter assembly 270. The selvage part 288 of the filter assembly 270 is formed in the vertical line of the shaft support part 255.

As shown in FIG. 11 the shaft support part 255 and the selvage part 288 are formed such that the press fitting part 287 of the lower opening part 282 is fitted into the through hole 232 of the bottom 231 when the pump unit 240 is pressed downward with the shaft support part 255 and the selvage part 288 fitted in the guide part 235.

The upper case 271 is formed to block the upper opening of the cylindrical portion 281. A second partition wall 273, which projects toward the projection 284 of the first partition wall 283, is formed on an upper end portion 272 of the upper case 271. By attaching the upper case 271 to lower case 280, two spaces, which are divided into right and left spaces, are formed between the upper end portion 272 and the first partition wall 283.

An opening 274, which communicates with the left space in FIG. 11, is formed in the upper end portion 272. The supply fuel filter 290 is provided in the opening 274. The supply fuel filter 290 is a nonwoven fabric formed from a similar material to the pumping fuel filter 291. The supply fuel filter 290 is attached to the opening 274, for example, by welding or insert molding.

A first connection 275, which communicates with the left space in FIG. 11, is formed on the upper end portion 272. The first connection 275 is connected to the supply pump suction opening 247 a. Furthermore, a second connection 276, which communicates with the right space shown in FIG. 11, is formed on the upper end portion 272. The second connection 276 is connected to the pumping suction opening 247 b.

By assembling the cases 271, 280 configured in the above-mentioned manner, two passages, more specifically, a supply fuel passage 292 whose inlet is the opening 274 and whose outlet is the first connection 75, and a pumping fuel passage 293 whose inlet is the lower opening part 282 and whose outlet is the second connection 276, are formed inside the filter assembly 270. The lower opening part 282 in the third embodiment corresponds to an “inlet.”

The fuel filter 250, which surrounds an outer circumference of the fuel pump 241, is provided on the outer circumferential side of the fuel pump 241. The fuel filter 250 filters the fuel, which has been discharged from the supply pump discharge opening 248 a of the fuel pump 241.

The fuel filter 250 is received in the filter case 251. The filter case 251 is made of resin, and has a generally circular ring-shaped space in which the fuel filter 250 is received. The filter case 251 supports the fuel pump 241 against a wall portion on its inner circumferential side.

The upper end portion 252 of the filter case 251 has a connection 253 connected to the supply pump discharge opening 248 a. A fuel passage 254, through which the connection 253 and the fuel filter 250 communicate, is formed in the filter case 251. The fuel, which has been discharged from the supply pump discharge opening 248 a, flows into the fuel filter 250 through the fuel passage 254.

The pressure regulator 260 is provided at a lower end portion of the filter case 251. The pressure regulator 260 regulates the pressure of the fuel, which has flowed out of the fuel filter 250. The fuel whose pressure has been regulated by the pressure regulator 260 is discharged through the discharge opening 261 formed in the filter case 251. The fuel that has been discharged from the discharge opening 261 is supplied to the internal combustion engine outside the fuel tank 211 through the hose 262 and the fuel discharge pipe 221, which are connected to the discharge opening 261. Surplus fuel produced when the pressure of fuel is regulated in the pressure regulator 260 is discharged into the subtank 230 through a drain port (not shown).

The filter case 251 has a snap fitting part (not shown), which engages a pawl part (not shown) formed in the filter assembly 270, so as to hold the filter assembly 270.

The shaft support part 255, which projects toward the guide part 235 of the subtank 230 from an outer circumferential wall surface of the filter case 251, is formed on the outer circumferential wall surface. The shaft support part 255 has a supporting hole 256, which a lower end side of the shaft 224 is inserted into and thereby supports a side surface of the shaft 224. A diameter of the supporting hole 256 is determined, such that the shaft 224 is movable in the supporting hole 256. A color 226, which prevents the shaft 224 from falling out of the supporting hole 256, is attached to the leading end of the shaft 224.

By inserting the shaft 224 in the supporting hole 256, the displacement of the pump unit 240 in the circumferential direction as well as in the radial direction with respect to the flange 220 is restricted, and accordingly only its displacement in the axial direction is allowed.

As shown in FIG. 11, a coil spring 225 whose upper end portion is supported by the flange 220 and whose lower end portion is supported by the shaft supporting part 255 is provided for the shaft 224. The coil spring 225 presses the pump unit 240, together with the subtank 230, on the bottom 213 of the fuel tank 211. Accordingly, because of the expansion or contraction of the fuel tank 211 made of resin due to a variation of its internal pressure caused by the temperature change or due to a change of a fuel amount, the pump unit 240 and the subtank 230 are made to follow the bottom 213 of the fuel tank 211, even if a distance between the opening 212 and the bottom 213 of the fuel tank 211 varies.

Next, workings of the fuel supply system 210 are explained below, By actuating the electric motor part 246 to drive the impeller 244 to rotate, suction force for fuel is generated in the supply pump part 242 and the pumping part 243.

Due to the above fuel suction force, fuel in the subtank 230 is suctioned into the supply pump part 242 along the supply fuel passage 292 through the supply fuel filter 290. The pressure of the suctioned fuel is increased in the supply pump part 242, and the fuel is discharged through the supply pump discharge opening 248 a.

The fuel discharged from the discharge opening 248 a flows into the fuel filter 250 through the fuel passage 254. The fuel, which has flowed into the fuel filter 250, is filtered through the fuel filter 250, and then flows into the pressure regulator 260. After that, the pressure of the fuel, which flowed into the pressure regulator 260, is regulated and the fuel is discharged through the discharge opening 261. The fuel, which has been discharged from the discharge opening 261, is supplied to the internal combustion engine through the hose 262 and the fuel discharge pipe 221.

On the other hand, fuel outside the subtank 230 is suctioned from the pumping fuel filter 291 into the pumping part 243 along the pumping fuel passage 293. The pressure of the suctioned fuel is increased in the pumping part 243, and the fuel is discharged into the subtank 230 through the pumping discharge opening 248 b.

Next, the assembly of the fuel supply system 210 of the third embodiment is explained below with reference to FIGS. 14A, 14B. FIG. 14A illustrates a state of the fuel supply system 210 before attaching an assemblage of the flange 220 and the pump unit 240 to the subtank 230. FIG. 14B illustrates a state of the fuel supply system 210 when the pump unit 240 is attached to the subtank 230. The assembly operation of the fuel supply system 210 according to the third embodiment is performed by people.

As shown in FIG. 14A, the assemblage of the flange 220 and the pump unit 240 is arranged on the opening side of the subtank 230. Since the color 226 for preventing the flange 220 from slipping off is provided for the leading end of the flange 220, the pump unit 240 does not fall out from the shaft 224 even when only the flange 220 is held by an operator.

Next, as shown in FIG. 14B, the operator holds the flange 220, and a filter assembly 270-side of the pump unit 240 is inserted into the subtank 230 from its opening side toward its bottom 231. The operator fits the two selvage parts 288 through the guide part 235 when inserting pump unit 240 into the subtank 230. Then, the operator pushes in the pump unit 240 further toward the bottom 231 of the subtank 230 with the selvage part 288 fitted through the guide part 235.

After this, the operator fits the two shaft supporting parts 255 through the guide part 235 similar to the selvage part 288. After the shaft supporting part 255 is fitted through the guide part 235, the operator pushes in the pump unit 240 further toward the bottom 231. The guide part 235 guides the selvage part 288 and the shaft supporting part 255 through the guide part 235, and guides the lower opening part 282 of the filter assembly 270 into the through hole 232 formed in the bottom 231.

Subsequently, as shown in FIG. 14B, the operator pushes in the flange 220 further downward with the press fitting part 287 of the lower opening part 282 in the through hole 232. Accordingly, a leading end of each shaft 224 is pushed in against urging force of the spring 225 and contacts the corresponding selvage part 288.

The operator pushes in the flange 220 further downward even after the leading end of the shaft 224 contacts the selvage part 288. Accordingly, the force for pushing in is transmitted to the press fitting part 287, and the lower opening part 282 is press-fitted into the through hole 232. The operator loosens the force applied to the flange 220 when the lower opening part 282 is press-fitted into the through hole 232. This completes the assembly operation of the fuel supply system 210.

In the fuel supply system 210 having a structure, whereby the lower opening part 282, through which fuel outside the subtank 230 is suctioned, is inserted into the through hole 232 formed in the bottom 231 of the subtank 230, the lower opening part 282 and the through hole 232 are located in blind spots in relation to the operator when the operation is carried out to insert the lower opening part 282 into the through hole 232. Consequently, the operating efficiency is reduced, and the reduction of manufacturing cost has been conventionally hindered. However, in the third embodiment, the guide part 235 and the shaft supporting part 255, which is guided by the guide part 235, are provided in the position (between the side wall 234 of the subtank 230 and an outer circumferential sidewall surface of the pump unit 240) which is seen from the operator. Accordingly, the operator can easily perform the assembly operation even if the operator does not see the lower opening part 282 or the through hole 232. As a result, the operating efficiency greatly improves, and thereby the manufacturing cost of the fuel supply system 210 is reduced.

In the third embodiment, the member, which is guided by the guide part 235, is used as the shaft supporting part 255 which supports the shaft 224. Accordingly, the structure of the filter case 251 is simplified, and thereby the manufacturing cost of the fuel supply system 210 is further reduced.

In the third embodiment, the selvage part 288 that is fitted through the guide part 235 is formed on the lower case 280, in which the lower opening part 282 is formed. Accordingly, the lower opening part 282 is reliably conducted into the through hole 232 formed on the bottom 231.

In the third embodiment, the guide part 235 corresponds to a “guiding portion”, and the shaft supporting part 255 and the selvage part 288 correspond to “guided portions.”

In the third embodiment, the shaft supporting part 255 formed in the filter case 251 and the selvage part 288 formed in the filter assembly 270 are fitted through the guide part 235, so that the lower opening part 282 is guided into the through hole 232. The shaft supporting part 255 and the selvage part 288 are provided along a direction of the insertion. Accordingly, when the pump unit 240 is inserted in the subtank 230, the position of the pump unit 240 is stabilized. Therefore, oblique fitting of the lower opening part 282 with respect to the through hole 232 is limited, and thereby defects caused in assembling the fuel supply system 210 are limited. As a result, the manufacturing cost of the fuel supply system 210 is further reduced.

Since the selvage part 288 is formed in the vertical line of the shaft 224, the lower opening part 282 is easily press-fitted into the through hole 232 only by pushing in the flange 220 downward. Thus, the operator pushes in the pump unit 240 downward without putting his/her hands between the flange 220 and the filter case 251 of the pump unit 240, so that the operating efficiency improves. The selvage part 288 that is formed below the shaft supporting part 255 is located in a position, which the leading end of the shaft 224 penetrating through the supporting hole 256 of the shaft supporting part 255 contacts. Because of the above structure, the operation to bring the leading end of the shaft 224 into contact with the selvage part 288 and push the lower opening part 282 into the through hole 232 is easily performed by only pushing in the flange 220 downward to move the shaft 224. Therefore, the manufacturing cost of the fuel supply system 210 is further reduced.

The upper end portion of the guide part 235 may become broader in the upward direction. As well, the shaft supporting part 255 and the selvage part 288 may become narrower in the downward direction. Accordingly, the operating efficiency improves in fitting the shaft supporting part 255 and the selvage part 288 through the guide part 235.

In addition, only the shaft supporting part 255 or only the selvage part 288 may be fitted through the guide part 235. By the above configuration as well, the operating efficiency improves greatly in comparison with conventional technologies.

Fourth Embodiment

Next, a fourth embodiment of the invention is described below. The same numerals are used for indicating substantially the same components as the third embodiment, and their descriptions are omitted. Only characteristic parts of the fourth embodiment are explained below.

In the fourth embodiment, as shown in FIG. 15, a projection portion 257, which is fitted through the guide part 235, is formed on the side surface of the filter case 251. Unlike the third embodiment, the projection portion 257 does not have a function of supporting the shaft 224. Even in such a case, only by fitting the projection portion 257 through the guide part 235 to insert a pump unit 240 a into the subtank 230, the lower opening part 282 is press-fitted into the through hole 232.

In the fourth embodiment as well, the selvage part 288 formed on the filter assembly 270 is located in the vertical line of the supporting hole 256 of the shaft supporting part 255. Accordingly, only by pushing in the flange 220, the press fitting of the lower opening part 282 into the through hole 232 is easily performed.

Moreover, as shown in FIG. 16, a projection portion 258, which is fitted through the guide part 235, may be formed below the projection portion 257 in addition to the selvage part 288. Accordingly, the position of the pump unit 240 a is stabilized when the pump unit 240 a is inserted in the subtank 230.

Fifth Embodiment

Next, a fifth embodiment of the invention is explained below. The same numerals are used for indicating substantially the same components as the third and fourth embodiments, and their descriptions are omitted. Only characteristic parts of the fifth embodiment are explained below.

In the fifth embodiment, unlike the third and fourth embodiments, a member guided by the guide part 235 is not formed integrally with the filter case 251, but formed on a member, which is different from the filter case 251.

FIG. 17 illustrates a bracket 2100 having a projection portion 2102 as a guided portion.

As shown in FIG. 17, the bracket 2100 includes a partly notched generally annular main body part 2101 having a projection portion 2102. The projection portion 2102 is formed to project radially from a side surface of the main body part 2101. As shown in FIG. 19, the number of the projection portions 2102 is the same as the number of the guide parts 235 on the side wall 234 of the subtank 230. The shaft supporting part 255, which supports the shaft 224, is formed on the side wall 234 such that it does not overlap with the guide part 235, in addition to the guide part 235.

As shown in FIG. 18, the bracket 2100 is attached to the filter case 251 by fixing the main body part 2101 to the upper end portion 252 of the filter case 251 through press-fitting, adhesion, welding, or an engagement apparatus (not shown).

As shown in FIGS. 14A, 14B in the third embodiment, the lower opening part 282 of the filter assembly 270 is guided into the through hole 232 by pushing in the pump unit 240, to which the bracket 2100 is attached, toward the bottom 231 of the subtank 230 with the projection portion 2102 fitted through the guide part 235. Then, by further pushing in the pump unit 240, the lower opening part 282 is press-fitted into the through hole 232.

In the fifth embodiment, the projection portion 2102, which is guided by the guide part 235, is formed on the bracket 2100 that is different from the filter case 251. Accordingly, even if a portion that is guided by the guide part 235 is not formed in the pump unit 240, the operating efficiency improves in assembling the fuel supply system 210 by only attaching the bracket 2100 to the pump unit 240.

Sixth Embodiment

Next, a sixth embodiment of the invention is explained below. The same numerals are used for indicating substantially the same components as the third to fifth embodiments, and their descriptions are omitted. Only the characteristic parts of the sixth embodiment are explained below.

In the sixth embodiment, the shape and arrangement of a guide part 235 a differ from the third to fifth embodiments. FIGS. 21, 22 illustrate a bracket 2110 which has an engagement part 2112 guided by the guide part 235 a. FIGS. 23, 24 illustrate another bracket 2120, which is different from FIGS. 21, 22.

In the sixth embodiment, as shown in FIGS. 20A, 20B, the guide part 235 a is not formed on the inner circumferential side but on the outer circumferential side of the side wall 234. As shown in FIG. 20B, the guide part 235 a has a shape of a U when viewed from above and is formed on the side wall 234 to form a gap 236 between the guide part 235 a and the side wall 234. As shown in FIG. 20B, two guide parts 235 a are formed on both sides of the through hole 232.

As shown in FIGS. 21, 22, similar to the fifth embodiment, the engagement part 2112 that is guided by the guide part 235 a is formed in a main body part 2111 of a bracket 2110, which is fixed to the upper end portion 252 of the filter case 251 by press-fitting or the like. The number of the engagement parts 2112 is the same as the number of the guide parts 235 a. Two pawl parts 2113, which engage a lower end portion 237 (FIG. 20A) of the guide part 235 a after they are inserted in the gap 236, are formed at a leading end of each of the engagement parts 2112.

In the example shown in FIG. 22, the pawl part 2113 is formed to deform along a circumferential direction of the main body part 2111. After passing through the gap 236, the pawl parts 2113 spread in the circumferential direction away from each other so as to engage the lower end portion 237 of the guide part 235 a. Accordingly, the separation of the pump unit 240 from the subtank 230 is limited.

As shown in FIG. 21, by pushing in the pump unit 240, to which the bracket 2110 is attached, toward the bottom 231 of the subtank 230 with the engagement part 2112 inserted into the gap 236 that is formed in the guide part 235 a as shown in FIGS. 14A, 14B in the third embodiment, the lower opening part 282 of the filter assembly 270 is guided into the through hole 232. Then, by further pushing in the pump unit 240, the lower opening part 282 is press-fitted into the through hole 232.

A bracket 2120 in FIGS. 23, 24 may be employed as a modification to the sixth embodiment. In the above modification, a pawl part 2123 at a leading end of an engagement part 2122, which is formed in a main body part 2121 of the bracket 2120, is formed to deform in a radial direction of the main body part 2121. Even in the case of the pawl part 2123 having the above shape, the pawl part 2123 engages the lower end portion 237 of the guide part 235 a. Accordingly, the separation of the pump unit 240 from the subtank 230 is limited.

In the sixth embodiment, a member that is guided by the guide part 235 a is formed on the brackets 2110, 2120, which are different from the filter case 251. Accordingly, even if the portion guided by the guide part 235 a is not formed on the pump unit 240, the operating efficiency in assembling the fuel supply system 210 is improved by only attaching the brackets 2110, 2120.

Additional advantages and modifications will readily occur to those skilled in the art. The invention in its broader terms is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described. 

1. A fuel supply system that is configured to supply fuel in a fuel tank to a fuel consumption apparatus, the system comprising: a subtank that is received in the fuel tank and has a communicating hole at a bottom of the subtank, wherein: a part of fuel, which is stored in the fuel tank, is stored in the subtank; and an outside and an inside of the subtank communicate through the communicating hole; a pump unit received in the subtank and having a supply pump part, which supplies fuel in the subtank to the fuel consumption apparatus, and a pumping part, which pumps up fuel outside the subtank into the subtank, wherein the pumping part has a suction part, which suctions fuel outside the subtank through the communicating hole; and an urging means for urging the pump unit one of directly and indirectly toward the bottom of the subtank.
 2. The fuel supply system according to claim 1, wherein the suction part has a fitted part, which is fitted into the communicating hole of the subtank.
 3. The fuel supply system according to claim 2, wherein the urging means includes: a lid member that closes an opening formed on a ceiling portion of the fuel tank in a vertical direction thereof; a projection portion formed one of directly and indirectly on the pump unit to project in a radial direction of the pump unit; and an urging member that is held by the lid member at one end of the urging member and is held by the projection portion at the other end of the urging member, wherein the urging member urges the pump unit one of directly and indirectly toward the bottom of the subtank.
 4. The fuel supply system according to claim 3, wherein: the lid member includes a shaft extending toward a bottom of the fuel tank; and the projection portion includes a guiding portion that holds a side surface of the shaft and that guides the pump unit in an axial direction of the shaft.
 5. The fuel supply system according to claim 4, further comprising a shaft supporting part at a lateral bottom end portion of the pump unit in a vertical direction thereof, wherein the shaft supporting part supports the shaft on an extension line of the shaft.
 6. The fuel supply system according to claim 1, wherein: the urging means includes a main body part that supports the pump unit one of directly and indirectly; and the main body part has an engagement part, which engages the subtank, and an urging part, which urges the pump unit one of directly and indirectly toward the bottom of the subtank.
 7. The fuel supply system according to claim 6, wherein the urging part has a shape of a plate, and the urging part is configured to bend so as to urge the pump unit.
 8. The fuel supply system according to claim 6, wherein the urging part is a coil spring.
 9. The fuel supply system according to claim 6, wherein the suction part has a fitted part, which is fitted into the communicating hole of the subtank.
 10. The fuel supply system according to claim 6, wherein: the subtank opens on an opposite side of the bottom of the subtank; the engagement part of the urging means is fitted on the subtank in a direction from an opening side toward the bottom of the subtank, so that the engagement part engages the subtank; and the urging part of the urging means urges an end portion of the pump unit, which is on the opening side of the subtank, one of directly and indirectly toward the bottom of the subtank.
 11. The fuel supply system according to claim 1, wherein the pump unit further includes: an impeller having an outer circumference side vane part on an outer circumferential side of the impeller, and an inner circumference side vane part on an inner circumferential side of the impeller; a passage member having an outer circumference side pump passage, which is formed in a shape of a circular arc along the outer circumference side vane part, and an inner circumference side pump passage, which is formed in a shape of a circular arc along the inner circumference side vane part; and an electric motor part configured to drive the impeller to rotate, wherein the supply pump part includes the outer circumference side vane part and the outer circumference side pump passage, and the pumping part includes the inner circumference side vane part and the inner circumference side pump passage.
 12. The fuel supply system according to claim 1, wherein the suction part includes: a case having therein a partition wall, which defines a supply fuel passage and a pumping fuel passage, wherein: an inlet of the supply fuel passage opens in the subtank, and an outlet of the supply fuel passage is connected to the supply pump part; and an inlet of the pumping fuel passage opens outside the subtank through the communicating hole, and an outlet of the pumping fuel passage is connected to the pumping part; a supply fuel filter disposed in the supply fuel passage; and a pumping fuel filter disposed in the pumping fuel passage.
 13. The fuel supply system according to claim 1, wherein: the subtank has a guiding portion on an inner wall surface of the subtank; and the guiding portion guides the suction part into the communicating hole.
 14. The fuel supply system according to claim 1, wherein: the subtank is formed in a cylindrical shape having a bottom portion, and opens at an upper portion of the subtank in a vertical direction thereof; the suction part has a lower opening part, through which fuel outside the subtank is suctioned by the pumping part, at an end portion of the pump unit that is opposed to the bottom of the subtank; the pump unit has a discharge opening, through which fuel suctioned through the lower opening part is discharged into the subtank by the pumping part at the end portion of the pump unit; the lower opening part penetrates through the communicating hole such that the lower opening part projects from the bottom of the subtank into the outside of the subtank; and the fuel supply system further comprising: a guided portion on a side portion of the pump unit, wherein the guided portion projects in a radial direction of the pump unit; and a guiding portion on a side wall of the subtank, wherein the guiding portion is arranged to guide the guided portion such that, when the pump unit is inserted in the subtank in a direction from an opening side toward the bottom of the subtank, the lower opening part is conducted into the communicating hole.
 15. The fuel supply system according to claim 14, wherein: the fuel tank has an opening, through which the subtank and the pump unit are inserted in the fuel tank, on an upper wall of the fuel tank in a vertical direction thereof; the fuel supply system further comprising; a lid member that blocks the opening; and a shaft that extends from the lid member toward the bottom of the subtank and that connects the lid member and the pump unit; and the guided portion includes a supporting part, which supports the shaft.
 16. The fuel supply system according to claim 14, wherein: the pump unit includes: a fuel pump portion having the pumping part; and the suction part disposed at an end portion of the fuel pump portion and having a filter element, which filters fuel suctioned through the lower opening part, and a case, which has the lower opening part at one end portion of the case; and the guided portion is formed on a side portion of the case.
 17. The fuel supply system according to claim 14, wherein: the guided portion includes a first guided portion and a second guided portion; and the first guided portion and the second guided portion are formed on the side portion of the pump unit along a direction in which the pump unit is inserted in the subtank.
 18. The fuel supply system according to claim 17, wherein: the fuel tank has an opening, through which the subtank and the pump unit are inserted in the fuel tank, on an upper wall of the fuel tank in a vertical direction thereof; the fuel supply system further comprising: a lid member that blocks the opening; and a shaft that extends from the lid member toward the bottom of the subtank and that connects the lid member and the pump unit; the first guided portion includes a supporting part, which supports the shaft; and the second guided portion is formed below the first guided portion.
 19. The fuel supply system according to claim 18, wherein: the pump unit includes: a fuel pump portion having the pumping part; and the suction part disposed at an end portion of the fuel pump portion and having a filter element, which filters fuel suctioned through the lower opening part, and a case, which has the lower opening part at one end portion of the case; the shaft penetrates through the supporting part of the first guided portion; and the second guided portion is located such that, when the shaft is pushed in toward the bottom of the subtank, a leading end of the shaft, which has penetrated through the supporting part, reaches the second guided portion.
 20. The fuel supply system according to claim 14, wherein the guided portion is formed on a guiding member, which is attached to the pump unit and is different from the pump unit. 